1. Field of the Invention
The present invention is related to the technology of tuning an output enable signal, and more particularly adapted for tuning the output enable signal of a gate driver.
2. Description of Related Art
Because of the advantages of low power consumption, no radiation, and so forth, liquid crystal display (LCD) seems to have become a mainstream among display products. Generally speaking, an LCD basically includes a gate driver, a source driver, and a panel. It is noted that the conventional LCD still face rewriting problem when being driven. Such kind of problem is described in detail below.
FIG. 1 illustrates a conventional rewriting phenomenon. Referring to FIG. 1, Signal G1_output is an output scan signal which the gate driver provides to a first scan line, wherein the first scan line is coupled to pixel transistors of a first-row. Signal G2_output is an output scan signal which the gate driver provides to a second scan line, wherein the second scan line is coupled to pixel transistors of a second-row. Signal S2_output is a data signal which the source driver provides to pixel transistors of the second-row.
In an ideal condition, the time for Signal G1_output and Signal G2_output to drop from high voltage to low voltage is about 0 second. Likewise, the time for rising from low voltage to high voltage is about 0 second as well, as indicated by the dotted line in FIG. 1. However, in actual situation, the voltages of Signal G1_output and Signal G2_output do not form perfect rectangular waveforms. Delay occurs when the voltages drop from high voltage to low voltage or rise from low voltage to high voltage, as illustrated by the solid line in FIG. 1.
Referring to FIG. 1, a turn-on voltage of a pixel transistor is assumed to be Vth. At Time T1, pixel transistors of the first-row pixel are changed from turn-on status to turn-off status. Moreover, at Time T2, pixel transistors of the second-row are changed from turn-off status to turn-on status. That is, in the time period between Time T1 and T2, pixel transistors of the first-row and pixel transistors of the second-row are turned on together. Hence, Signal S2_output simultaneously performs writing on pixel transistors of the first-row and the second-row in the period between Time T1 and T2, which is called rewriting phenomenon. However, in an ideal condition, Signal S2_output should perform writing only on pixel transistors of the second-row.